1. Field of the Invention
The present invention relates to a Bluetooth master selecting method, a Bluetooth master selecting program and a Bluetooth apparatus which serve to select a master from the Bluetooth apparatus for building a Bluetooth network.
2. Description of the Related Art
In a Bluetooth network, there are a Bluetooth apparatus to be a master and a Bluetooth apparatus to be a slave. The master is connected to a large number of slave devices in a one-many connection and serves as a device for generating a connection request (Create Connection) by itself, and the slave is connected to only the master one-on-one in the one-many connection and serves as a device for accepting the connection request (receiving Page Scan).
In a conventional Bluetooth device, a method of determining a master or a slave is roughly divided into two methods. A first method is a factor for determining whether the type of a device is the master or the slave, and a cell phone is determined to be the master and a head set is determined to be the slave, for example.
A second method serves to select the master or the slave by the operation of a user. For example, in the case in which household electric appliances build the Bluetooth network, the user is to carry out an operation for selecting the master or the slave for respective devices.
FIG. 13 is a diagram for explaining a state in which the electric appliance thus builds the Bluetooth network. In FIG. 13, 1301 to 1303 denote Bluetooth devices T1, T2 and T3 respectively, and 1311 to 1313 denote radio communication regions of the Bluetooth devices T1, T2 and T3 respectively.
Since the Bluetooth devices T1 and T3 are positioned on the outside of the mutual radio communication regions, the user is to set T1, T2 and T3 to be the slave, the master and the slave based on a method of operating the devices, respectively. A procedure and method for determining the master or the slave has been prescribed in Non-Patent Document 1 (Specification of the Bluetooth System Version 1.1, Feb. 22, 2001, [Retrieved on May 30, 2003], Internet <URL:http://www.bluetooth.com>) as Bluetooth standards.
Only in the case in which the master and the slave are determined uniquely based on the structure of a device, the first method can be applied. When a plurality of Bluetooth devices is to be connected to each other, particularly, such a determining method cannot be used.
In the second method, a great deal of time and labor is required for manually operating each device by the user. Furthermore, a general user does not know the Bluetooth technology well. For this reason, it is hard to decide an optimum master.
More specifically, in the Bluetooth network, one Bluetooth device to be the master is permitted for each subnet, and a communication is always carried out through the Bluetooth device to be the master. Also in the case in which the communication is to be carried out between slaves 1 and 2, it is performed in a course of the slave 1 to the slave 2 via the master.
Therefore, a Bluetooth device capable of being stably connected to more Bluetooth devices is the optimum master. However, it is hard for the general user to determine the optimum master. Even if an optimum Bluetooth device is set to be the master, moreover, it is necessary to newly select the optimum master when the arrangement of the Bluetooth device is changed. As a result, a great deal of time and labor is required.